System for detecting intrusions by devices with openable casing

A system for intrusion detections for devices with split casing, such as financial terminals or ‘datafonos’, PIN pads or other devices with split casing for which is required to have security mechanisms to detect intrusion attempts in the interior of the device, that being of the type of those who incorporate a control circuit that incorporates means for intrusion detection in the device associated with a switch associated, as well, to one of the split cases of the device, is characterized with the existence of electrical contacts 16, 17 and 18 on top of which is set out a three state switch 1, consisting in a, preferably, single body, with resilient properties, in which are defined an outer member 2 and two actuators 3 and 4, joint electrically to each other by means of the contact conductive surfaces 7-43-8-42-9, is such a way that in a non-operating situation or on releasing of the corresponding split case, the outer member 2 makes electrical contact with the electrical contact 16 of the electronic circuit board 36, meanwhile the two actuators 3 and 4, due to the resilient nature of the device, do not contact with the electrical contacts 17 and 18;

• having foreseen that in assembled disposition the most interior actuator 4 contacts with the electrical contact 18, by means of elastic deformation of the switch, closing the security circuit, while the intermediate actuator 3 has a length slightly inferior than the one of the inner actuator 4, in a way that it only contacts with the intermediate electrical contact 17 when the switch supports a pressure superior to the one of the assembling foreseen for it, triggering the intrusion signal.